Question: $-\dfrac{9}{5} + \dfrac{9}{3} = {?}$
Explanation: $ = - {\dfrac{9 \times 3}{5 \times 3}} + {\dfrac{9 \times 5}{3 \times 5}} $ $ = - {\dfrac{27}{15}} + {\dfrac{45}{15}} $ $ = - \dfrac{{27} + {45}}{15} $ $ = \dfrac{18}{15}$